Gwen Stefani hopped in the car with late night host James Corden for a round of his recurring segment Carpool Karaoke and answered the question we’ve all been wondering: how does she keep her youthful look?

Stefani attributes her glow to a person rather than a facial cream.

“What happened was, my life blew up ... after that I kind of started falling in love, then I wrote a whole record about that, and it's almost like, that’s what the facelift is, I think,” she says with a knowing smile, clearly referencing her relationship with Blake Shelton.

“So I should tell my wife, if you meet a country music singer who happens to be an absolute hunk, you’ll just go back in time,” Corden concludes as Stefani laughs.

The singer spends nearly 15 minutes singing through her repertoire with Corden, including No Doubt hits, songs from her solo career like "The Sweet Escape" and her more recent song "Used to Love You," discussing things like emojis in between tracks. Before they get to Corden’s job, though, they get some very special passengers: George Clooney and Julia Roberts.

Clooney and Roberts are great sports, and all four celebrities join in a singalong of Stefani’s hit "Hollaback Girl," making for a delightful and hilarious clip. Even the distinguished actor Clooney wasn’t shy about spelling out “B-A-N-A-N-A-S” loud and proud. The karaoke trip concluded with an epic version of Queen’s “We Are the Champions,” which all four also sang with gusto. The entire segment is packed with hilarious moments and unexpected quips, making it a must-watch clip.